Reactive Oxygen Species Triggered Oxidative Degradation of Polystyrene in the Gut of Superworms (Zophobas atratus Larvae)

Oxidative decomposition of polystyrene (PS) by insects has been previously demonstrated, yet little is known about the oxidation mechanism and its effect on the metabolism of plastics within the insect gut. Here, we demonstrate the generation of reactive oxygen species (ROS) in the gut of superworms (Zophobas atratus larvae) under different feeding trails, which in turn induced the oxidative decomposition of ingested PS. The ROS were commonly generated in the larva gut, and PS consumption resulted in a significant increase of ROS with a maximum ·OH of 51.2 μmol/kg, which was five times higher than in the bran feeding group. Importantly, scavenging of ROS significantly decreased the oxidative depolymerization of PS, indicating a vital role of ROS in effective PS degradation in the gut of superworms. Further investigation suggested that the oxidative depolymerization of PS was caused by the combinatorial effect of ROS and extracellular oxidases of gut microbes. These results demonstrate that ROS were extensively produced within the intestinal microenvironment of insect larvae, which greatly favored the digestion of ingested bio-refractory polymers. This work provides new insights into the underlying biochemical mechanisms of plastic degradation in the gut.

Enhanced degradation of microplastics during sludge composting via microbially-driven Fenton reaction

It has been increasingly documented that the hydroxyl radical (•OH) can promote the transformation of organic contaminants such as microplastics (MPs) in various environments. However, few studies have sought to identify an ideal strategy for accelerating in situ MPs degradation through boosting the process of •OH production in practical applications. In this work, iron-mineral-supplemented thermophilic composting (imTC) is proposed and demonstrated for enhancing in situ degradation of sludge-based MPs through strengthening •OH generation. The results show that the reduction efficiency of sludge-based MPs abundance was about 35.93% in imTC after treatment for 36 days, which was 38.99% higher than that of ordinary thermophilic composting (oTC). Further investigation on polyethylene-microplastics (PE-MPs) suggested that higher abundance of •OH (the maximum value was 408.1 μmol·kg^-1) could be detected on the MPs isolated from imTC through microbially-mediated redox transformation of iron oxides, as compared to oTC. Analyses of the physicochemical properties of the composted PE-MPs indicated that increased •OH generation could largely accelerate the oxidative degradation of MPs. This work, for the first time, proposes a feasible strategy to enhance the reduction efficiency of MPs abundance during composting through the regulation of •OH production.

Reactive oxygen species accelerate humification process during iron mineral-amended sludge composting

The production of hydroxyl radicals (OH) has been documented during composting. However, the effect of OH on composting efficiency remains unclear. Here, iron mineral supplemented thermophilic composting (imTC) is proposed and demonstrated for enhancing OH production and accelerating the maturation of composting. The results indicated that the maximum OH production of imTC was 1922.74 μmol·kg^-1, which increased by 1.39 times than that of ordinary thermophilic composting (oTC). Importantly, the increase of OH could greatly enhance organic matter degradation and humic substances formation during imTC, resulting in shorting the maturity time by 25 %. Enrichment of laccase-producing bacteria resulted in higher laccase activity (31.85 U·g^-1) in imTC compared with oTC (23.82 U·g^-1), which may have contributed to the higher level of humification in imTC treatment. This work, for the first time, proposes a feasible strategy for improving composting efficiency through the regulation of OH production during aerobic composting.

Extensive production and evolution of free radicals during composting

The production of free radicals has been widely documented in natural systems, where they play an important role in most organic matter and contaminants transformation. Here, the production and evolution of free radicals were systematically investigated during composting. Results indicated that multiple reactive oxygen species and environmentally persistent free radicals (G-factor 2.003-2.004) were generated with dynamic changes during composting. The ·OH yield fluctuated significantly with a maximum content of 365.7-1,262.3 μmol/kg at the thermophilic phase of composting, which was closely correlated with the changes of Fe (II) (Pearson's r = 0.928-0.932) and the electron-donating capacity of humus (Pearson's r = 0.958-0.896) during composting. Further investigation suggested that microorganisms driven iron/humus redox conversion could contribute to the production and dynamic changes of free radical during composting. These findings highlight the abiotic processes involving free radicals, and provide a new perspective for humification and contaminants removal during composting.

Degradation of microplastics by hydroxyl radicals generated during microbially driven humus redox transformation

The production of ·OH during transformation of redox active substances has been increasingly documented, and it causes the ageing or degradation of microplastics (MPs) in natural systems. However, the contribution of the humus redox cycle to ·OH generation and MPs transformation has previously been overlooked, even though it is ubiquitous in alternating anoxic-oxic environments. In this work, the integrated pathways of ·OH generation during the redox transformation of humic acids (HAs) and the contribution of this ·OH to the transformation of MPs were investigated for the first time. It was found that ·OH could be produced continuously during successive cycles of redox transformation of HAs mediated by Bacillus thermotolerans SgZ-8 through exogeneous HAs dependent and independent pathways. O₂·^- and H₂O₂ were identified as the key intermediate species, which were produced by both microbial aerobic respiration and HA oxidation. The ·OH generated by HA redox cycles could lead to a weight loss of PS-MPs of 18.1% through oxidative degradation during a period of 8 weeks of anoxic-oxic incubation. The EDC of HAs is closely related to ·OH production, which could have a large influence on the effectiveness of oxidative degradation of PS-MPs during various HAs redox cycles in temporarily anoxic environmental systems. These findings provide new insights into ·OH formation and MPs transformation through microbially driven humus redox cycles in alternating anoxic-oxic environments.

Free radicals accelerate in situ ageing of microplastics during sludge composting

Composting is the last "barrier" for microplastics (MPs) in the entry of organic solid wastes into the environment. The transformation of MPs is thought to be mainly driven by microorganisms during composting, whereas the contribution of abiotic processes that involve free radicals is often overlooked. Herein, we provide initial evidence for the generation of free radicals during sludge composting, including environmental persistent free radicals and reactive oxygen species, which accelerate the oxidative degradation of MPs. The ·OH yield of composting fluctuated greatly from 23.03 to 277.18 μmol/kg during composting, which was closely related to the dynamic changes in Fe(II) (R² = 0.926). Analyses of the composted MPs physicochemical properties indicated that MPs were aged gradually with molecular weights decrease from 18% to 27% and carbonyl index value increase from 0.23 to 0.52. Further investigation suggested that the microbially-mediated redox transformation of iron oxides could occur on the MPs surface accompanied by the production of abundant free radicals, thereby leading to the damage of MPs during composting. These results reveal the critical role of free radicals in MPs ageing under oxic/anoxic alternation conditions of composting and provide new insights into the bio-chemical mechanism of contaminant removal or transformation during sludge composting.

Development, Characterization, and Evaluation of SLN-Loaded Thermoresponsive Hydrogel System of Topotecan as Biological Macromolecule for Colorectal Delivery

BACKGROUND

Chemotherapeutic drugs cause severe toxicities if administered unprotected, without proper targeting, and controlled release. In this study, we developed topotecan- (TPT-) loaded solid lipid nanoparticles (SLNs) for their chemotherapeutic effect against colorectal cancer. The TPT-SLNs were further incorporated into a thermoresponsive hydrogel system (TRHS) (TPT-SLNs-TRHS) to ensure control release and reduce toxicity of the drug. Microemulsion technique and cold method were, respectively, used to develop TPT-SLNs and TPT-SLNs-TRHS. Particle size, polydispersive index (PDI), and incorporation efficiency (IE) of the TPT-SLNs were determined. Similarly, gelation time, gel strength, and bioadhesive force studies of the TPT-SLNs-TRHS were performed. Additionally, in vitro release and pharmacokinetic and antitumour evaluations of the formulation were done.

RESULTS

TPT-SLNs have uniformly distributed particles with mean size in nanorange (174 nm) and IE of ~90%. TPT-SLNs-TRHS demonstrated suitable gelation properties upon administration into the rat's rectum. Moreover, drug release was exhibited in a control manner over an extended period of time for the incorporated TPT. Pharmacokinetic studies showed enhanced bioavailability of the TPT with improved plasma concentration and AUC. Further, it showed significantly enhanced antitumour effect in tumour-bearing mice as compared to the test formulations.

CONCLUSION

It can be concluded that SLNs incorporated in TRHS could be a potential source of the antitumour drug delivery with better control of the drug release and no toxicity.

Enhanced in situ Pb(II) passivation by biotransformation into chloropyromorphite during sludge composting

Composting is an effective technology for the disposal and utilization of solid biowastes. However, conventional composting is inefficient for the passivation of heavy metals in solid biowastes, thus limiting the applications of compost derived from solid biowaste. Here, a thermophilic biomineralization strategy was proposed and demonstrated during sludge composting for in situ heavy metals passivation via thermophiles inoculation. It was found that Thermus thermophilus could promote the transformation of Pb(II) into the most stable chloropyromorphite [Pb₅(PO₄)₃Cl, K_sp = 10^-84.4] during composting. After 40 days of composting with T. thermophilus FAFU013, the most insoluble residual fractions of Pb increased by 16.0% (from 76.5% to 92.5%), which was approximately 3 times higher than that of the uninoculated control. The DTPA-extractable Pb decreased to 11.5%, which was 14.4% less compared with the uninoculated control, indicating a significant Pb passivation by inoculation of T. thermophilus FAFU013. A series of batch experiments revealed that Pb(II) could be rapidly accumulated by selective biosorption and gradually transformed into chloropyromorphite through the biomineralization of T. thermophilus FAFU013. This study provides new insight into the mechanism of heavy metal passivation during composting and the problem associated with the disposal of Pb-contaminated solid biowastes through the biomineralization of thermophiles.

Enhanced in situ biodegradation of microplastics in sewage sludge using hyperthermophilic composting technology

Land spreading of sewage sludge is a major source of environmental microplastics (MPs) contamination. However, conventional sludge treatments are inefficient at removing sludge-based MPs. Herein, hyperthermophilic composting (hTC) technology is proposed and demonstrated in full-scale (200 t) for in situ biodegradation of sludge-based MPs. After 45 days of hTC treatment, 43.7% of the MPs was removed from the sewage sludge, which is the highest value ever reported for MPs biodegradation. The underlying mechanisms of MPs removal were investigated in lab-scale polystyrene-microplastics (PS-MPs) biodegradation experiments. The hTC inoculum degraded 7.3% of the PS-MPs at 70 °C in 56 days, which was about 6.6 times higher than that of the conventional thermophilic composting (cTC) inoculum at 40 °C. Analyses of the molecular weight and physicochemical properties of the PS-MPs residuals indicated that hyperthermophilic bacteria in hTC accelerated PS-MPs biodegradation through excellent bio-oxidation performance. High-throughput sequencing suggested that Thermus, Bacillus, and Geobacillus were the dominant bacteria responsible for the highly efficient biodegradation during hTC. These results reveal the critical role of hyperthermophilic bacteria in MPs biodegradation during hTC, highlighting a promising strategy for sludge-based MPs removal from the real environment.

The effect of the heart rate lowering drug Ivabradine on hemodynamics in atherosclerotic mice

The heart rate lowering drug Ivabradine was shown to improve cardiac outcome in patients with previous heart failure. However, in patients without heart failure, no beneficial effect of Ivabradine was observed. Animal studies suggested a preventive effect of Ivabradine on atherosclerosis which was due to an increase in wall shear stress (WSS), the blood flow-induced frictional force exerted on the endothelium, triggering anti-inflammatory responses. However, data on the effect of Ivabradine on WSS is sparse. We aim to study the effect of Ivabradine on (i) the 3D WSS distribution over a growing plaque and (ii) plaque composition. We induced atherosclerosis in ApoE-/- mice by placing a tapered cast around the right common carotid artery (RCCA). Five weeks after cast placement, Ivabradine was administered via drinking water (15 mg/kg/day) for 2 weeks, after which the RCCA was excised for histology analyses. Before and after Ivabradine treatment, animals were imaged with Doppler Ultrasound to measure blood velocity. Vessel geometry was obtained using contrast-enhanced micro-CT. Time-averaged WSS during systole, diastole and peak WSS was subsequently computed. Ivabradine significantly decreased heart rate (459 ± 28 bpm vs. 567 ± 32 bpm, p < 0.001). Normalized peak flow significantly increased in the Ivabradine group (124.2% ± 40.5% vs. 87.3% ± 25.4%, p < 0.05), reflected by an increased normalized WSS level during systole (110.7% ± 18.4% vs. 75.4% ± 24.6%, p < 0.05). However, plaque size or composition including plaque area, relative necrotic core area and macrophage content were not altered in mice treated with Ivabradine compared to controls. We conclude that increased WSS in response to Ivabradine treatment did not affect plaque progression in a murine model.

Temporal and spatial changes in wall shear stress during atherosclerotic plaque progression in mice

Wall shear stress (WSS) is involved in atherosclerotic plaque initiation, yet its role in plaque progression remains unclear. We aimed to study (i) the temporal and spatial changes in WSS over a growing plaque and (ii) the correlation between WSS and plaque composition, using animal-specific data in an atherosclerotic mouse model. Tapered casts were placed around the right common carotid arteries (RCCA) of ApoE^-/- mice. At 5, 7 and 9 weeks after cast placement, RCCA geometry was reconstructed using contrast-enhanced micro-CT. Lumen narrowing was observed in all mice, indicating the progression of a lumen intruding plaque. Next, we determined the flow rate in the RCCA of each mouse using Doppler Ultrasound and computed WSS at all time points. Over time, as the plaque developed and further intruded into the lumen, absolute WSS significantly decreased. Finally at week 9, plaque composition was histologically characterized. The proximal part of the plaque was small and eccentric, exposed to relatively lower WSS. Close to the cast a larger and concentric plaque was present, exposed to relatively higher WSS. Lower WSS was significantly correlated to the accumulation of macrophages in the eccentric plaque. When pooling data of all animals, correlation between WSS and plaque composition was weak and no longer statistically significant. In conclusion, our data showed that in our mouse model absolute WSS strikingly decreased during disease progression, which was significantly correlated to plaque area and macrophage content. Besides, our study demonstrates the necessity to analyse individual animals and plaques when studying correlations between WSS and plaque composition.

[Significance of v-raf murine sarcoma viral oncogene homologue B1 in rheumatoid arthritis]

OBJECTIVE

To detect serum v-raf murine sarcoma viral oncogene homologue B1 (BRAF) protein levels and to investigate their clinical significance in rheumatoid arthritis (RA) patients.

METHODS

Serum samples were obtained from 78 RA patients, 32 osteoarthritis (OA) patients, 16 systemic lupus erythematosus (SLE) patients, 16 gout patients, 16 ankylosing spondylitis (AS) patients, 16 Sjogren syndrome (SS) patients and 30 healthy controls. BRAF protein in the sera was examined by enzyme-linked immunosorbent assay (ELISA). The associations between BRAF levels and the clinical features including age, sex, disease duration, swelling joints, tenderness joints, duration of moning stiffness, joint deformity, visual assessment scale (VAS) and extra articular manifestations and laboratory parameters including erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), disease activity score in 28 joints (DAS28), anti-cyclic citrullinated peptide (CCP) antibody, antikeratin antibody, antnuclear antibody (ANA), immunoglobulin and cytokines, such as TNF-α, IL-1β, IL-6 and IL-17A in RA patients were evaluated. Data analyses were performed by using SPSS 19.0 program.

RESULTS

The serum BRAF protein levels in the RA patients were significantly higher than those of other rheumatic diseases groups including OA, SLE, AS, SS, gout patients and healthy controls, the P value was 0.002, <0.001, <0.001, <0.001, 0.001 and <0.001 respectively. The level of serum BRAF protein in the RA patients showed a positive correlation with the rheumatoid factor (P=0.009) and IgA levels (P=0.006), but no correlation with clinical features, such as age and duration or other laboratory parameters, including CRP, ESR, anti-CCP antibody, IgM, IgG, TNF-α, IL-1β, IL-6 and IL-17A. The RA patients were further divided into normal levels of BRAF protein group and elevated levels of BRAF protein group. Compared with the clinical features and laboratory indexes of normal and elevated levels of BRAF protein groups in the RA patients, there was no significant difference between the two groups in age, duration, DAS28, CRP, ESR, RF, anti-CCP, IgA, IgG, IgM, TNF-α or IL-6.

CONCLUSION

The elevated level of BRAF protein in the RA patients showed that BRAF might play a role in the pathogenesis of RA. Further researches on BRAF gene expression may help to clarify the role of BRAF in RA.

Radiation-enhancing effect of sodium glycididazole in patients suffering from non-small cell lung cancer with multiple brain metastases: A randomized, placebo-controlled study

PURPOSE

Median survival of patients with brain metastases from non-small cell lung cancer is poor. This study was to investigate the radiation-enhancing effect of sodium glycididazole combined with whole-brain radiotherapy of multiple brain metastases from non-small cell lung cancer.

PATIENTS AND METHODS

Sixty-four patients with multiple brain metastases from non-small cell lung cancer were included: the study group (n=32) received whole-brain radiotherapy combined with sodium glycididazole at a dose of 700mg/m(2) intravenous infusion 30minutes before radiotherapy, three times a week; the control group (n=32) only received whole-brain radiotherapy. The primary end point was central nervous system (CNS) progression-free survival and overall survival. The treatment-related toxicity was also recorded.

RESULTS

The CNS disease control rate was better (90.6% vs 65.6%, P=0.016) in the study group than in the control group at 3 month of follow-up. The median CNS progression-free survival time was longer in the study group than in the control group (7.0 months vs 4.0 months, P=0.038). There was no significant difference of the median overall survival time between the study group and the control group (11.0 months vs 9.0 months, P=0.418). On the other hand, the treatment-related toxicity showed no statistically significant difference between these two groups (P>0.05).

CONCLUSIONS

The study indicated that sodium glycididazole was an effective, promising radiation-enhancing agent that improved CNS disease control rate, extended the median CNS progression-free survival time and was well tolerated in patients suffering from non-small cell lung cancer with multiple brain metastases.

Interleukin-21 induces migration and invasion of fibroblast-like synoviocytes from patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by synovial fibroblast hyperplasia and bone erosion. Fibroblast-like synoviocytes (FLS) play a pivotal role in RA pathogenesis through aggressive migration and matrix invasion, and certain proinflammatory cytokines may affect synoviocyte invasion. Whether interleukin (IL)-21 influences this process remains controversial. Here, we evaluated the potential regulatory effect of IL-21 on the migration, invasion and matrix metalloproteinase (MMP) expression in RA-FLS. We found that IL-21 promoted the migration, invasion and MMP (MMP-2, MMP-3, MMP-9, MMP-13) production in RA-FLS. Moreover, IL-21 induced activation of the phosphoinositide 3-kinase (PI3K), signal transducer and activator of transcription-3 (STAT-3) and extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) pathways, and blockage of these pathways [PI3K/protein kinase B (AKT) inhibitor LY294002, STAT-3 inhibitor STA-21 and ERK1/2 inhibitor PD98059] attenuated IL-21-induced migration and secretion of MMP-3 and MMP-9. In conclusion, our results suggest that IL-21 promotes migration and invasion of RA-FLS. Therefore, therapeutic strategies targeting IL-21 might be effective for the treatment of RA.

Copy number variations of HLA-I and activation of NKp30 pathway determine the sensitivity of gastric cancer cells to the cytotoxicity of natural killer cells

Nude mice are important in vivo model for characterization of cell malignancy behavior; however, many cancer cells fail to form tumors in it. Understanding this defective mechanism may provide novel insights into tumorigenesis and how tumor cells escape innate immunity. Whole-genome sequencing was conducted on two gastric cancer (GC) cells, BGC823 and AGS, which do and do not form tumors in nude mice, to identify their genomic differences relevant to natural killer (NK) cells. We found that the tumorigenic capacity of human GC cell lines was dependent on the recruitment and activation of NK cells in xenograft tumors. We used whole-genome sequence (WGS) on GC cell lines to identify potential genes controlling susceptibility to NK-mediated killing. The tumorigenic cell line BGC823 expressed high levels of HLA-I because of copy gain and was resistant to NK cell killing. In contrast, another cell line AGS expressing low levels of HLA-I with activated NKp30/MAPK/IL-12 (interleukin-12) or IL-2 (interleukin-2) pathway was susceptible to NK lysis. Treatment of tumor bearing mice with systemic administration of IL-12 in combination with intratumor injection of anti-HLA-I antibody significantly increased NK cell recruitment into xenograft tumors, which became sensitive to NK killing, resulting in reduced tumor progression. In human GC specimens, decreased HLA-I expression and increased NK cells surrounding tumor cells were correlated with decreased metastasis potential and better prognosis of patients. Our results provide a mechanistic basis for GC cells to escape NK lysis and a promising prospect of NK immunotherapy for GC cells.

Isolation of microsatellite loci for Rhodiola alsia (Crassulaceae), an important ethno-medicinal herb endemic to the Qinghai-Tibetan plateau

Rhodiola alsia, which has been used widely in traditional Chinese medicine for a considerable time, grows on moist habitats at high altitude near the snow line. Microsatellite loci were developed for R. alsia to investigate its population genetics. In total, 17 polymorphic microsatellites were developed based on ESTs from the Illumina HiSeq(TM) 2000 platform. The microsatellite loci were checked for variability using 80 individuals of R. alsia sampled from four locations on the Qinghai-Tibet Plateau. The total number of alleles per locus ranged from 10 to 20, and the observed heterozygosity ranged from 0.000 to 1.000. The null allele frequency ranged from 0.000 to 0.324. These microsatellites are expected to be helpful in future studies of population genetics in R. alsia and related species.

Serum C-reactive protein predicts poor prognosis in patients with locoregionally advanced nasopharyngeal carcinoma treated with chemoradiotherapy

BACKGROUND

We aimed to evaluate the association of serum C-reactive protein (crp) with prognosis in patients with locoregionally advanced nasopharyngeal carcinoma treated with chemoradiotherapy.

METHODS

We retrospectively reviewed 79 patients with locoregionally advanced nasopharyngeal carcinoma (cT3-4N0-3M0) treated with chemoradiotherapy. Chemoradiotherapy consisted of external-beam radiotherapy to the nasopharynx (70-80 Gy), the lymph node-positive area (60-70 Gy), and the lymph node-negative area (50-60 Gy) combined with 3 cycles of various platinum-based regimens delivered at 3-week intervals. Elevated crp was defined as more than 8 mg/L. The survival rate was calculated using the Kaplan-Meier method, and univariate and multivariate analyses (Cox proportional hazards model) were used to identify factors significantly associated with prognosis.

RESULTS

During the median follow-up of 3.9 years (range: 1-5.5 years), 23 patients died from nasopharyngeal cancer. The 5-year cancer-specific survival (css) rate was 62.90%. Before chemoradiotherapy, 18 patients had high serum crp; the css rate in that subgroup was significantly worse than the rate in the remaining patients (p = 0.0002). Multivariate analysis showed that crp was an independent prognostic indicator of css, with a hazard ratio of 3.04 (95% confidence interval: 1.22 to 7.55; p = 0.017). Among the 18 patients with elevated serum crp, 9 achieved normal serum crp after chemoradiotherapy, of whom 5 remained living with no evidence of recurrence or metastasis during follow-up. By contrast, the remaining 9 patients in whom serum crp did not normalize after chemoradiotherapy died within 4.2 years.

CONCLUSIONS

Elevated serum crp before treatment predicts poor prognosis in patients with locoregionally advanced nasopharyngeal carcinoma treated with chemoradiotherapy.

Differential response of human gingival fibroblasts to titanium- and titanium-zirconium-modified surfaces

BACKGROUND AND OBJECTIVE

Gingival fibroblasts are responsible for the constant adaptation, wound healing and regeneration of gingival connective tissue. New titanium-zirconium (TiZr) abutment surfaces have been designed to improve soft tissue integration and reduce implant failure compared with titanium (Ti). The aim of the present study was first to characterize a primary human gingival fibroblast (HGF) model and secondly to evaluate their differential response to Ti and TiZr polished (P), machined (M) and machined + acid-etched (modMA) surfaces, respectively.

MATERIAL AND METHODS

HGF were cultured on tissue culture plastic or on the different Ti and TiZr surfaces. Cell morphology was evaluated through confocal and scanning electron microscopy. A wound healing assay was performed to evaluate the capacity of HGF to close a scratch. The expression of genes was evaluated by real-time RT-PCR, addressing: (i) extracellular matrix organization and turnover; (ii) inflammation; (iii) cell adhesion and structure; and (iv) wound healing. Finally, cells on Ti/TiZr surfaces were immunostained with anti-ITGB3 antibodies to analyze integrin β3 production. Matrix metalloproteinase-1 (MMP1) and inhibitor of metallopeptidases-1 (TIMP1) production were analyzed by enzyme-linked immunosorbent assays.

RESULTS

On tissue culture plastic, HGF showed no differences between donors on cell proliferation and on the ability for wound closure; α-smooth muscle actin was overexpressed on scratched monolayers. The differentiation profile showed increased production of extracellular matrix components. Ti and TiZr showed similar biocompatibility with HGF. TiZr increased integrin-β3 mRNA and protein levels, compared with Ti. Cells on TiZr surfaces showed higher MMP1 protein than Ti surfaces, although similar TIMP1 protein production. In this in vitro experiment, P and M surfaces from both Ti and TiZr showed better HGF growth than modMA.

CONCLUSION

Taking into account the better mechanical properties and bioactivity of TiZr compared with Ti, the results of the present study show that TiZr is a potential clinical candidate for soft tissue integration and implant success.

Functional analysis of 30K proteins during silk gland degeneration by a caspase-dependent pathway in Bombyx

The 30K proteins are involved with important functions in the growth and development of Bombyx mori. In this study, the synthesis and regulation of 30K proteins were examined during the degeneration of Bombyx silk glands. On day 3 of the fifth instar, the protein level of 30Kc19 was low, whereas the silk proteins were rapidly synthesized. However, synthesis and accumulation of the 30Kc19 protein significantly increased at the prepupal stage and on day 1 of the pupal stage. At this stage, the silk gland cells were filled with 30Kc19 and genomic DNA. Moreover, the transcript levels of the 30K-encoding genes, including 30Kc6, 30Kc12, 30Kc19 and 30Kc23 were up-regulated during the degeneration of the Bombyx silk glands. During the time that the levels of the 30Kc19 protein were significantly up-regulated, it is notable that the transcript levels of the BmAtg8, BmAtg6 and BmDronc genes dramatically increased to regulate the programmed cell death of this gland. On day 1 of the pupal stage, intense fragmentation of genomic DNA occurred in the silk gland cells, and the putative active form of caspase was detected in the cytoplasm, showing the complete degradation of the silk glands in one day. In conclusion, the 30K proteins are synthesized in high concentrations, while proteolysis mediates silk gland degeneration in Bombyx by a caspase-dependent pathway. We propose that the 30K proteins may be nutrients and energy vectors to be absorbed by the developing tissues of pupae or moths.

ANXA2 remodels the microstructures of caco2 cells

ANXA2 was reported as a multiple tumors relevant gene expressed excessively in many tumor tissue types, especially in the cancers from digestion system, and its aberrant expression enhances the malignant properties of cancer cells. We suppose that the microstructure heterogeneity is important to maintain the malignancy of cancer cells, and excessive ANXA2 expression enhance the malignancy by remodeling the microstructures of cancer cells. To validate the proposal, the ANXA2-/-caco2 cell line was generated and the changes of the microstructures in the ANXA2 deleted and wild type caco2 cells were observed under fluorescence microscope, laser scanning confocal microscope and electron microscope. We found that ANXA2 deletion induced the pseudopodia shorted and spared, non-stained areas increased, mitochondria decreased, and the expression and polymerization of F-actin and β-tubulin changed. By the findings above, it is firstly reported in this paper that the ANXA2 excessive expression induces the significant changes of the microstructures in cancer cells. Combining our previous data together, our results indicate that ANXA2 excessive expression enhances the malignancy of cancers partially by remodeling the cell microstructures.

Role of Amino Acids and Vitamins in Nutrition of Mesophilic Methanococcus spp

In this study we found that autotrophic methanococci similar to Methanococcus maripaludis obtained up to 57% of their cellular carbon from exogenous amino acids. About 85% of the incorporation was into protein. Primarily nonpolar and basic amino acids and glycine were incorporated; only small amounts of acidic and some polar amino acids were taken up. An additional 10% of the incorporation was into the nucleic acid fraction. Because little CO(2) was formed from the C-amino acids, little metabolism of the amino acids occurred. Therefore the growth stimulation by amino acids was probably due to the sparing of anabolic energy requirements. Of the amino acids incorporated, only alanine was also a sole nitrogen source for these methanococci. In contrast, Methanococcus vannielii and "Methanococcus aeolicus" are autotrophic methanococci which did not incorporate amino acids and did not utilize alanine as a sole nitrogen source. Although glutamine served as a sole nitrogen source for the autotrophic methanococci and Methanococcus voltae, a heterotrophic methanococcus, growth was due to chemical deamination in the medium. M. voltae requires leucine and isoleucine for growth. However, these amino acids were not significant nitrogen sources, and alanine was not a sole nitrogen source for the growth of M. voltae. The branched-chain amino acids were not extensively metabolized by M. voltae. Pantoyl lactone and pantoic acid were readily incorporated by M. voltae. The intact vitamin pantothenate was neither stimulatory to growth nor incorporated. In conclusion, although amino acids and vitamins are nutritionally important to both autotrophic and heterotrophic methanococci, generally they are not subject to extensive catabolism.

A novel assay for extracellular matrix remodeling associated with liver fibrosis: An enzyme-linked immunosorbent assay (ELISA) for a MMP-9 proteolytically revealed neo-epitope of type III collagen

OBJECTIVES

Accumulation of extracellular matrix (ECM) components and increased matrix-metalloprotease (MMPs) activity are hallmarks of fibrosis. We developed an ELISA for quantification of MMP-9 derived collagen type III (CO3) degradation.

DESIGN AND METHODS

A monoclonal antibody targeting a specific MMP-9 cleaved fragment of CO3 was used for development of a competitive ELISA. The assay was investigated in serum and tissues from bile duct ligated rats (BDL).

RESULTS

The ELISA showed no cross-reaction with either intact CO3, or other collagens. The intra- and inter-assay CV were below 10%. Liver fibrosis was demonstrated in BDL animals by semi quantitative scoring (P<0.0001). Serum levels of CO3-610 increased 2.5 fold in BDL animals (P<0.001). The CO3-610 levels were 5 fold higher in ex vivo cultures of fibrotic livers compared to controls (P<0.001).

CONCLUSION

We have developed a novel ELISA for measuring a specific fragment CO3 generated by MMP-9 important in pathogenesis of liver fibrosis.

[Investigation on natural foci of autumn-winter type tsutsugamushi disease in Shandong province]

OBJECTIVE

In order to provide basic data of tsutsugamushi disease in Shandong province, for the control and prevention of this disease in residents and army-men.

METHODS

Aetiological, serological and epidemiological methods were used to investigate the natural foci of autumn-winter type tsutsugamushi disease.

RESULTS

The peak of tsutsugamushi disease epidemic in Shandong province was in October with cases in this month accounted for 80% of all in a year, that showed autumn-winter type. The main reservoir hosts were Apodemus agrarius, Rattus norvegicus and Cricetulus triton, accounted for 82.87%, 85.47% and 13.04% respectively. It was confirmed that natural infection existed among Leptotrombidium (L.) scutellare, L. palpalis, L. linhuaikonense and Walchia pacifica. The main vector of transmission was Leptotrombidium scutellare. 41 strains of Rickettsia tsutsugamushi were isolated from the blood samples of patients, rodents and chigger mites but with weak toxicity. 90% of the serotypes of the strains belonged to Gilliam type. The distribution of the cases had a sporadic nature. More than 80% of the cases were young or middle aged peasants. Clinical symptoms were mild, with some differences in different areas.

CONCLUSION

The natural foci type of tsutsugamushi disease in Shandong could be divided into plain and hilly types.

[Apoptosis of human melanoma cell line WM-983A by p16 gene transduction]

OBJECTIVE

To further understand the mechanism of action of the tumor-suppressor gene p16.

METHODS

An adenoviral expression vector with full length cDNA of p16 gene insert was constructed (Ad-p16) and transfected into WM-983A cells, the p16 gene of which was point mutated at codon 126. The effect of exogenous p16 gene on the growth of WM-983A cells was examined in vitro and in vivo.

RESULTS

Expression of p16 gene in WM-983A cells was confirmed by Western blot. The in vitro growth of the Ad-p16 transfected WM-983A cells was significantly inhibited (inhibition rate: 78%) as compared to mock (Ad-LacZ) transfected WM-983A cells. Colony-forming activity in vitro of the Ad-p16 transfected WM-983A cells was completely inhibited. Morphologically, the Ad-p16 transfected cells appeared apoptotic which was confirmed by the appearance of pre-G1 on flow cytometry and DNA fragmentation. The growth of WM-983A xenografts in nude mice was retarded by intra-tumoral injection of Ad-p16.

CONCLUSION

p16 gene participates in the induction of cell apoptosis. It is promising to use it for gene therapy of cancer, especially when combined with other apopptosis-inducing agents.

Design of a transferrin-proteinase inhibitor conjugate to probe for active cysteine proteinases in endosomes

A new technique has been developed to identify active proteinases in endosomes that does not require prior isolation of organelles and extraction of the active enzymes. [125I]Iodotyrosylalanyldiazomethane was reversibly conjugated to transferrin to selectively deliver it to endosomes. The protein was conjugated to the inhibitor via a disulphide bond using N-succinimidyl 3-(2-pyridyldithio)propionate. The inhibitor portion of the conjugate bound irreversibly to active cathepsins B and L, and subsequently the reacted enzymes were separated from the transferrin after SDS/PAGE under reducing conditions. Uptake of the protein-inhibitor conjugate and incorporation of inhibitor into cathepsins was blocked at 4 degreesC, demonstrating that the conjugate enters cells by receptor-mediated endocytosis. Furthermore, endocytosed transferrin-inhibitor conjugate could be recycled back to the extracellular medium and binding to the transferrin receptor could be blocked by native transferrin. Labelling of the enzymes was not blocked by incubating cells at 16 degreesC, consistent with the majority of the reagent being targeted to endosomes. The inhibited enzymes remained conjugated to transferrin, showing that the disulphide bond between the transferrin and inhibitor was not reduced in the endosome. Results from these studies show that endosomes contain both intermediate and late biosynthetic forms of active cathepsin B, which are indistinguishable from those found in mature lysosomes. These results indicate that the active enzymes in endosomes are not early biosynthetic forms in transit to lysosomes but most probably enter the endosome via retrograde traffic from the lysosome.

Hyaluronan and CD44 expression in minor salivary gland tumors

OBJECTIVES

Hyaluronan (HA) and CD44 are most likely associated with tumor invasion and metastasis. Malignancies with different degrees of aggressiveness may express different levels and patterns of HA and CD44. The aim of this project was to examine the distribution of HA and CD44 in minor salivary gland tumors to determine if staining could be correlated with biologic behavior or tumor type.

MATERIALS AND METHODS

Biotinylated hyaluronan binding protein as a probe for HA and monoclonal antibodies specific for CD44 were used to stain classic examples of the five most commonly encountered minor salivary gland tumors: monomorphic adenomas, pleomorphic adenomas, polymorphous low grade adenocarcinomas, mucoepidermoid carcinomas, and adenoid cystic carcinomas.

RESULTS

Tumor cells of monomorphic adenomas were negative for both HA and CD44, and tumor capsules were intensely HA-positive. Pleomorphic adenomas exhibited HA and CD44 positivity in both mesenchymal and epithelial components, and HA in capsular tissues. All malignant salivary gland tumors expressed similar intense HA in tumor stroma. HA staining was more intense in stroma than in parenchymal cells. Tumor cells of most adenoid cystic carcinomas were HA-positive, while most polymorphous low grade adenocarcinomas were HA-negative. HA was uniformly distributed throughout supporting stroma of high and low grade malignancies, except for two polymorphous low grade adenocarcinomas (PLGAs) in which HA was more intense at the invading edge of the tumors. CD44 expression was seen only in tumor cells (not stroma) of malignancies, and was of similar intensity in both low and high grade tumors.

CONCLUSIONS

Differences in the expression of HA and CD44 among different types of salivary gland tumors were noted. These findings, however, could not be correlated with known biologic behaviors of the tumor groups studied. Immunohistochemical staining of salivary gland tumors for HA and CD44 may be useful in separating monomorphic adenoma, polymorphous low grade adenocarcinoma and adenoid cystic carcinoma, lesions that may be difficult to distinguish with routine light microscopy.

Quantification of cathepsins B and L in cells

A method for quantifying active cysteine proteinases in mammalian cells has been developed using an active-site-directed inhibitor. Fluoren-9-ylmethoxycarbonyl(di-iodotyrosylalanyl)-diaz omethane (Fmoc-[I2]Tyr-Ala-CHN2) was prepared and shown to react irreversibly with cathepsins B and L, but not with cathepsin S. The non- and mono-iodo forms of the inhibitor reacted with all three enzymes. These results demonstrate that, unlike cathepsins B and L, cathepsin S has a restricted S2-binding site that cannot accommodate the bulky di-iodotyrosine. Fmoc-[I2]Tyr-Ala-CHN2 was able to penetrate cells and react with active enzymes within the cells. A radiolabelled form of the inhibitor was synthesized and the concentration of functional inhibitor was established by titration with papain. This inhibitor was used to quantify active cysteine proteinases in cultured cells. Active cathepsin B was found to be expressed by all of the cells studied, consistently with a housekeeping role for this enzyme. Active forms of cathepsin L were also expressed by all of the cells, but in different quantities. Two additional proteins were labelled in some of the cells, and these may represent other non-characterized proteinases. Higher levels of active cathepsins B and L, and an unidentified protein of Mr 39000, were found in breast tumour cells that are invasive, compared with those that are not invasive. From the data obtained, it can be calculated that the concentrations of both active cathepsins B and L in lysosomes can be as high as 1 mM, each constituting up to 20% of total protein in the organelle. This new technique provides a more direct procedure for determining the proteolytic potential of cellular lysosomes.

Azapeptides as inhibitors and active site titrants for cysteine proteinases

Ester and amide derivatives of alpha-azaglycine (carbazic acid, H2NNHCOOH), alpha-azaalanine, and alpha-azaphenylalanine (i.e., Ac-l-Phe-NHN(R)CO-X, where X = H, CH3, or CH2Ph, respectively) were synthesized and evaluated as inhibitors of the cysteine proteinases papain and cathepsin B. The ester derivatives inactivated papain and cathepsin B at rates which increased dramatically with leaving group hydrophobicity and electronegativity. For example, with 8 (R = H, X = OPh) the apparent second-order rate constant for papain inactivation was 67 600 M-1 s-1. Amide and P1-thioamide derivatives do not inactivate papain, nor are they substrates; instead they are weak competitive inhibitors (0.2 mM < Ki < 4 mM). Inactivation of papain involves carbamoylation of the enzyme, as demonstrated by electrospray mass spectrometry. Active site titration indicated a 1:1 stoichiometry for the inactivation of papain with 8, and both inactivated papain and cathepsin B are highly resistant to reactivation by dialysis (t1/2 > 24 h at 4 degrees C). Azaalanine derivatives Ac-L-Phe-NHN(CH3)CO-X inactivate papain ca. 400- 900-fold more slowly than their azaglycine analogues, consistent with the planar configuration at Nalpha of the P1 residue and the very substantial stereoselectivity of papain for L- vs D- residues at the P1 position of its substrates. Azaglycine derivative 9 (R = H, X = OC6H4NO2-p) inactivates papain extremely rapidly (>70 000 M-1 s-1), but it also decomposes rapidly in buffer with release of nitrophenol (kobs = 0.13 min-1); under the same conditions 8 shows <7% hydrolysis over 24 h. This nitrophenol release probably involves cyclization to an oxadiazolone since 17 (R = CH3, X = OC6H4NO2-p), which cannot form an isocyanate, releases nitrophenol almost as rapidly (kobs = 0.028 min-1). Cathepsin C, another cysteine proteinase with a rather different substrate specificity (i.e., aminopeptidase), was not inactivated by 8, indicating that the inactivation of papain and cathepsin B by azapeptide esters is a specific process. Their ease of synthesis coupled with good solution stability suggests that azapeptide esters may be useful as active site titrants of cysteine proteinases and probes of their biological function in vivo.

Control of breast tumor cell growth using a targeted cysteine protease inhibitor

The purpose of this study was to determine whether inhibition of lysosomal proteolysis could be used to selectively inhibit proliferation of tumor cells. The lysosomal cysteine protease inhibitor 9-fluorenylmethyloxycarbonyl-tyrosylalanyl-diazomethane was found to inhibit growth of the breast cancer cell lines SK-Br-3 and MCF-7. A humanized monoclonal antibody (huMAb 4D5) directed against the extracellular domain of p185HER2 specifically inhibited growth of the SK-Br-3 cells, which overexpress this antigen. The antibody and inhibitor together showed enhanced inhibition of growth of the SK-Br-3 cells only. When the protease inhibitor was radiolabeled and conjugated to the antibody (huMAb 4D5-125I-Tyr-Ala-CHN2) it was selectively bound to and taken up by the SK-Br-3 cell line. The conjugated inhibitor was delivered and targeted to cathepsin B and an unidentified protein of Mr 39,000 in the SK-Br-3 cells. Internalization of huMAb 4D5-125I-Tyr-Ala-CHN2 and inhibitor labeling of the proteins were temperature-dependent processes. huMAb 4D5-Tyr-Ala-CHN2 was significantly more effective in inhibiting proliferation of SK-Br-3 cells than the inhibitor-free analogue but was ineffective against MCF-7 cells. The results in this report show that targeting of cysteine protease inhibitors can selectively control tumor cell growth and that targeted cysteine protease inhibitors could prove valuable in the development of novel anticancer immunotherapies.

Expression of urokinase-type plasminogen activator and its receptor during ovarian follicular development

Although tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) are believed to be involved in the biochemical cascade leading to extracellular matrix degradation during ovulation, the presence and possible role of urokinase-type PA (uPA) and its receptor (uPAR) in follicular wall remodeling during follicular development are poorly understood. In the current studies, we have examined their presence in the rat ovary and compared the changes in both uPA and uPAR expression with those of tPA and PAI-1 during follicular growth in vivo. The presence of these proteins in various follicular cells at different stages of maturation was evaluated by immunolocalization and ELISA. Abundance of respective messenger RNA in granulosa cells from preantrallearly antral, midantral and preovulatory follicles and the residual ovaries was determined by Northern blot analysis. Whereas uPA transcript and protein levels were highest at the earliest stage of follicular growth examined and decreased markedly before the expected time of ovulation, the opposite was true for uPAR. In addition, tPA and PAI-1 messenger RNA abundance and protein contents were low in both granulosa and residual ovarian tissue during early follicular development but increased thereafter, reaching highest levels at the preovulatory period. These findings demonstrate for the first time the presence of uPAR in ovarian follicles and its developmental expression. The coincidental rise in uPAR and PAI-1 proteins during the preovulatory period may be important for the regulation of extracellular matrix remodelling before ovulation. The reciprocal expression of uPA and tPA during follicular development are consistent with the notion that these proteases have different biological functions in the ovary, i.e. tPA is involved in follicular wall remodelling before ovulation whereas uPA is important in extracellular matrix degradation during cell proliferation and migration that accompany follicle growth.

Nonenzymatic acetolactate oxidation to diacetyl by flavin, nicotinamide and quinone coenzymes

Acetolactate nonenzymatically reduced flavins, quinones and nicotinamide coenzymes in a time-dependent manner at physiological pH and moderate temperature. In the presence of excess acetolactate, the reduction of FAD and NAD+ followed pseudo-first-order kinetics. The rate of reduction was proportional to the concentration of acetolactate, and the rate constants at 37 degrees C and pH 7.5 were 4.8 x 10(-2) M-1 s-1 and 7.4 x 10(-3) M-1 s-1 for FAD and NAD+, respectively. In contrast, ubiquinone reduction followed pseudo-zero-order kinetics in the presence of excess acetolactate. At 37 degrees C and pH 7.5, the rate of reduction was proportional to the acetolactate concentration, and the apparent rate constant was 8.3 x 10(-6) s-1. In contrast to FAD, the rate of reduction of ubiquinone was higher at low pH. The kinetics of ubiquinone reduction suggested that the rate-limiting step was acetolactate decarboxylation and formation of the enolate anion, whereas the rate of FAD reduction was governed by the second-order reaction of the enolate anion. Following the oxidation, acetolactate was converted to diacetyl. Reduced FAD formed by the reaction with acetolactate generated a low rate of O2 consumption during assays of the oxygenase activity of acetohydroxy acid synthase. The reaction of acetolactate with quinones may provide a mechanism for the nonenzymatic formation diacetyl in whole milk.

[Apoptosis of tumor cells in lectin-dependent lymphokine-activated killer cell-mediated cytotoxicity]

By using DNA electrophoresis and propidium iodide (PI) staining flow cytometry (FACS) analysis, we studied the mechanisms of lymphokine-activated killer (LAK) cell-mediated cytotoxicity. In the presence of pokeweed mitogen (PWM), human LAK cells induced DNA fragmentation of two leukemic cell lines (U937 cells and Raji cells) and two solid tumor cell lines (SW1116 cells and Hep-2 cells), a hallmark of apoptosis. The reactions were carried out at the effector/target ratio of 1:1 and in 4 hr coculture. Pretreatment with RNA and protein synthesis inhibitors (actinomycin D and cycloheximide) did not prevent the target cells from apoptosis. As the TNF-resistant tumor cell lines such as SW1116 cells and Raji cells were also triggered to apoptosis, other factors than TNF would play the role. DNA-PI staining FACS analysis also suggested that a part of LAK cells underwent apoptosis to some extent during incubation with target cells. The results provide a new way to investigate the mechanisms of cytotoxicity of LAK cells and to enhance the efficacy of adoptive tumor therapy with LAK cells.

Purification and characterization of the oxygen-sensitive acetohydroxy acid synthase from the archaebacterium Methanococcus aeolicus

Acetohydroxy acid synthase (EC 4.1.3.18) of the archaebacterium Methanococcus aeolicus was purified 1,150-fold to homogeneity. The molecular weight of the purified enzyme was 125,000, and it contained only one type of subunit (M(r) = 58,000). The amino-terminal sequence had 46 to 57% similarity to those of the large subunits of the eubacterial anabolic enzymes and 37 to 43% similarity to those of the yeast and plant enzymes. The methanococcal enzyme had a pH optimum of 7.6. The pI, estimated by chromatofocusing, was 5.6. Activity required Mg2+ or Mn2+ ions, thiamine pyrophosphate, and a flavin. Flavin adenine dinucleotide, flavin mononucleotide, and riboflavin plus 10 mM phosphate all supported activity. However, activity was strongly inhibited by these flavins at 0.3 mM. The Michaelis constants for pyruvate, MgCl2, MnCl2, thiamine pyrophosphate, flavin adenine dinucleotide, and flavin mononucleotide were 6.8 mM, 0.3 mM, 0.16 mM, 1.6 microM, 0.4 microM, and 1.3 microM, respectively. In cell extracts, the enzyme was sensitive to O2 (half-life = 2.7 min with 5% O2 in the headspace), but the purified enzyme was less sensitive to O2 (half-life = 78.0 min with 20% O2). Reconstitution of the enzyme with flavin adenine dinucleotide increased the sensitivity to O2. Moreover, in the assay the homogeneous enzyme was rapidly inactivated by O2, and the concentration required for 50% inhibition (I50) was obtained with an atmosphere of 0.11% O2. The methanococcal enzyme has similarities to the eubacterial and eucaryotic enzymes, consistent with the ancient origin of the archaebacterial enzyme.

[Genetic profile of LIBP/1 inbred strain derived from the Kunming outbred stock of the mouse]

To make the genetic profile of the LIBP/1 inbred strain obtained from Kunming mice, the most widely used outbred stock in China, 26 loci were examined. The genotypes of four kinds of coat color genes were a/a, B/B, c/c and D/D. The results of testing 21 biochemical marker genes showed Akp-1b, Amy-1a, Car-2a, Ce-2a, Es-1b, Es-3a, Es-10a, Es-11a, Gpd-1a, Gpi-1a, Gus-1b, Hbbs, Idh-1a, Ldr-1a, Mod-1a, Mup-1b, Pep-3b, Pgm-a, Sep-1b, Tam-1c, and Trfb. The H-2 gene loci were Kb and Db.